1 files changed, 44 insertions, 0 deletions
diff --git a/intern/cycles/kernel/osl/shaders/node_layer_weight.osl b/intern/cycles/kernel/osl/shaders/node_layer_weight.osl
new file mode 100644
index 00000000000..1662be2cad1
--- /dev/null
+++ b/intern/cycles/kernel/osl/shaders/node_layer_weight.osl
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2011-2013 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "node_fresnel.h"
+#include "stdcycles.h"
+
+shader node_layer_weight(float Blend = 0.5,
+                         normal Normal = N,
+                         output float Fresnel = 0.0,
+                         output float Facing = 0.0)
+{
+  float blend = Blend;
+  float cosi = dot(I, Normal);
+
+  /* Fresnel */
+  float eta = max(1.0 - Blend, 1e-5);
+  eta = backfacing() ? eta : 1.0 / eta;
+  Fresnel = fresnel_dielectric_cos(cosi, eta);
+
+  /* Facing */
+  Facing = fabs(cosi);
+
+  if (blend != 0.5) {
+    blend = clamp(blend, 0.0, 1.0 - 1e-5);
+    blend = (blend < 0.5) ? 2.0 * blend : 0.5 / (1.0 - blend);
+
+    Facing = pow(Facing, blend);
+  }
+
+  Facing = 1.0 - Facing;
+}